Conventionally, there has been known a resin-made fuel tank including a resin-made fuel tank main body provided by joining an upper half and a lower half, a barrier sheet layer that is provided on substantially the whole part of an inner surface of the fuel tank main body and reduce permeation of a fuel, and mounting stays for mounting the fuel tank main body (see, for example, Patent Document 1). In Patent Document 1, the mounting stays extend outward from a joint portion of the upper half and the lower half.